Thanks for the very prompt response, Wayne! [Continued off-list.]
73 from Ian GM3SEK >-----Original Message----- >From: Elecraft [mailto:[email protected]] On Behalf Of >Wayne Burdick >Sent: 12 September 2015 22:12 >To: Ian White >Cc: 'Elecraft Reflector' >Subject: Re: [Elecraft] K3S/100 very low TX power > >Ian, > >This sounds like an intermittent connection somewhere, possibly in the 10- >W amplifier stage. > >Try re-tightening all of the hardware on the bottom covers, including the >screws that hold the PA device tabs to bottom cover B. Also try reseating >the 10-W amp module. > >If this doesn't help, try measuring the 0-dBm drive at the XVTR OUT jack. >For this purpose you need to put CONFIG:KXV3B into TEST mode. > >If you get a full 0 to 1.5 dBm output at XVTR OUT (into a 50-ohm load), but >low power output from the 10-W amp module, then the latter is probably >implicated. Look at both sides of the module very carefully to see if a >component is not soldered at one end, etc. This is rare but it can happen. > >Also look at the components on the RF board just behind the 10-W amp >module. > >I can give you more detailed signal tracing info if needed. > >Wayne >N6KR > > > >On Sep 12, 2015, at 1:57 PM, "Ian White" <[email protected]> wrote: > >> My K3S/100 has gone into an unusual state where the maximum power >> available - on any mode, any band - is about 1.5-2W. This is independent >> of any PWR setting above 1W, and the PA does not engage at higher PWR >> settings. >> >> All this began on Friday afternoon when I switched on the rig. The K3S >> had been working normally a few weeks ago, but hadn't been used for >> transmitting in the meantime. >> >> An external power meter confirmed that the TX could not deliver more >> than about 1.5-2W. This was confirmed again by the failure messages >> from a TX power calibration. While troubleshooting, I progressively >> uninstalled the KPA3 followed by the KPAIO3A adapter board, but with no >> change. Even in the simplest 10W configuration with only the small >> bridge board in place between the two PA connectors, the K3S would still >> only deliver 1.5-2W with no effective PWR control. >> >> I also tried most of the other common tests: unplugged everything else; >> reloaded an older saved configuration; EEINIT; reloaded the saved >> configuration again. No change. >> >> But I also noticed that the firmware was one release behind the times, >> so for lack of any other ideas I did a complete firmware upgrade to the >> latest MCU 5.35 / DSP 2.86 / FPF 1.24 - and it started working again! >> Normal power output up to 10W, and fully variable up to 100W after >> reinstalling the PA module. Another TX calibration confirmed that >> everything was fine. >> >> That pleasant surprise seemed to indicate that the problem had been >more >> related to firmware than to hardware. >> >> By Friday evening, I believed the problem had gone away... but I should >> have known better. >> >> Today it has failed again, exactly the same way as before. Reloading the >> same latest firmware didn't work a second time. >> >> So now it's the weekend and I'm all out of ideas. >> >> While I wait until Monday to contact Elecraft Support, could anyone in >> the group offer any suggestions, please? >> >> >> 73 from Ian GM3SEK >> >> >> >> >______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [email protected] > >______________________________________________________________ >Elecraft mailing list >Home: http://mailman.qth.net/mailman/listinfo/elecraft >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:[email protected] > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html >Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
